Dear Colleagues,

I wish to bring to your attention my recent work with Liping Liu on "A homogenization analysis of the field theoretic approach to the quasi-continuum method" to appear in the Journal of the Mechanics and Physics of Solids. Below is the abstract and attached is the preprint of the article. I will very much appreciate your comments and suggestions.

A Homogenization Analysis of the Field Theoretic Approach to the Quasi-Continuum Method

Hi everyone,

 does anyone know publications dealing with the coupled thermo-structural analysis (direct method) of CFRP using ANSYS?

http://www.springerlink.com/content/wx185g5301300521/fulltext.pdf

Macroscopic instabilities of fiber reinforced composites undergoing large deformations are studied. Analytical predictions for the onset of instability are determined by application of a new variational estimate for the behavior of hyperelastic composites. The resulting, closed-form expressions, are compared with corresponding predictions of finite element simulations. The simulations are performed with 3-D models of periodic composites with hexagonal unit cell subjected to compression along the fibers as well as to non-aligned compression. Throughout, the analytical predictions for the failures of neo-Hookean and Gent composites are in agreement with the numerical simulations.

It is found that the critical stretch ratio for Gent composites is close to the one determined for neo-Hookean composites with similar volume fractions and contrasts between the phases properties.

During non-aligned compression the fibers rotate and hence, for some loading directions, the compression along the fibers never reaches the level at which loss of stability may occur.

Two new papers grabbed my attention on my long unread list of journal tables of contents in Google Reader. 

1) The first was

Ideomechanics of transitory and dissipative systems associated with length, velocity, mass and energy by G.C. Sih

where it is stated that

" One of the rules of the development of IDM is that the “flow of nature” takes precedent when deducting and/or constructing quantitative results. It is hoped that

A very recent paper published a few minutes ago in Nature addresses the issue of friction laws at the nanoscale. Here is the abstract of the paper.Interested? here you can download the paper.

Here are some of my recent papers about mechanics of rubber material. They concern constitutive modelling, fatigue and fracture.

If you are interested in nano-calorimetry or combinatorial analysis, you might also find the following paper interesting. It was published as part of the MRS spring ‘06 meeting proceedings (http://www.mrs.org/s_mrs/sec_subscribe.asp?CID=6447&DID=175796&action=de...). This paper describes the parallel nano-differential scanning calorimeter (PnDSC), a new device for measuring the thermal properties of nano-scale material systems using a combinatorial approach.

Recent results on fluid-structure interaction for plates subject to high intensity air shocks are employed to assess the performance of all-metal sandwich plates compared to monolithic solid plates of the same material and mass per area. For a planar shock wave striking the plate, the new results enable the structural analysis to be decoupled from an analysis of shock propagation in the air. The study complements prior work on the role of fluid-structure interaction in the design and assessment of sandwich plates subject to water shocks. Square honeycomb and folded plate core topologies are considered. Fluid-structure interaction enhances the performance of sandwich plates relative to solid plates under intense air shocks, but not as significantly as for water blasts. The paper investigates two methods for applying the loading to the sandwich plate-responses are contrasted for loads applied as a time-dependent pressure history versus imposition of an initial velocity. Click here for the full paper.

Ting Zhu, Ju Li, Amit Samanta, Hyoung Gyu Kim and Subra Suresh

Nano-twinned copper exhibits an unusual combination of ultrahigh strength and high ductility, along with increased strain-rate sensitivity. We develop a mechanistic framework for predicting the rate sensitivity and elucidating the origin of ductility in terms of the interactions of dislocations with interfaces. Using atomistic reaction pathway calculations, we show that twin boundary (TB) mediated slip transfer reactions are the rate-controlling mechanisms of plastic flow. We attribute the relatively high ductility of nano-twinned copper to the hardenability of TBs as they gradually lose coherency during deformation. These results offer new avenues for tailoring material interfaces for optimized properties.

see the attached pdf file